on which the tangent line intersects the coordinate axes. From these one sees that when the point of tangency unlimitedly moves away from the origin (x0→∞,y0→∞formulae-sequencenormal-→subscriptx0normal-→subscripty0x_{0}\to\infty,\;y_{0}\to\infty), both intersection points tend to the origin. At the same time, the slopeb2⁢x0a2⁢y0superscriptb2subscriptx0superscripta2subscripty0\frac{b^{2}x_{0}}{a^{2}y_{0}} tends to a certain limitbaba\frac{b}{a}, because